Copyright Statement

Abstract

The objective of the present study was to investigate the influence of the encapsulation
efficiency and size of liposome on the oral bioavailability of griseofulvin-loaded liposomes.
Griseofulvin-loaded liposomes with desired characteristics were prepared from pro-liposome
using various techniques. To study the effect of encapsulation efficiency, three preparations of
griseofulvin, namely, griseofulvin aqueous suspension and two griseofulvin-loaded liposomes with
different amounts of griseofulvin encapsulated [i.e., F1 (32%) and F2(98%)], were administered to
rats. On the other hand, to study the effect of liposome size, the rats were given three different
griseofulvin-loaded liposomes of various sizes, generated via different mechanical dispersion
techniques [i.e., FTS (142 nm), MS (357 nm) and NS (813 nm)], but with essentially similar
encapsulation efficiencies (about 93%). Results indicated that the extent of bioavailability of
griseofulvin was improved 1.7–2.0 times when given in the form of liposomes (F1) compared to
griseofulvin suspension. Besides that, there was an approximately two-fold enhancement of the
extent of bioavailability following administration of griseofulvin-loaded liposomes with higher
encapsulation efficiency (F2), compared to those of F1. Also, the results showed that the extent of
bioavailability of liposomal formulations with smaller sizes were higher by approximately three
times compared to liposomal formulation of a larger size. Nevertheless, a further size reduction of
griseofulvin-loaded liposome (≤400 nm) did not promote the uptake or bioavailability of griseofulvin.
In conclusion, high drug encapsulation efficiency and small liposome size could enhance the oral
bioavailability of griseofulvin-loaded liposomes and therefore these two parameters deserve careful
consideration during formulation.